chrney wrote:It is connected to pin 6, not 8, thats a mistake in the diagram.

I connected the four wires to the I2c-backboard, GND, VCC, and the two that started with S. Nothing to the 16 pins on the LCD itself.

I suggest you check with multimeter on resistance setting, that the wires atually make connection from the connector actual pins to the actual pins of the desitinations. Update your wiring and or diagram to match exactly, as it is difficlut to help with mistakes on diagrams.

Connect GND to the actual GND pins on the Level Shifter

When powered up check actual voltages again as I do not believe you are actually wired up as you claim to be and have a missing connection or swapped connections.

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http://www.lottastaxi.com/movie.MOV
= movie with actual wiring. I hope you can see anything. It was the best way of illustrating this. It's just like I have the wiring on the drawing above. It's 4.3 meg, the movie.

Still nothing, but when checking i2cdetect with parameter 1, it does not hang anymore. But I can still not find the device.

http://www.lottastaxi.com/movie.MOV
= movie with actual wiring. I hope you can see anything. It was the best way of illustrating this. It's just like I have the wiring on the drawing above. It's 4.3 meg, the movie.

Still nothing, but when checking i2cdetect with parameter 1, it does not hang anymore. But I can still not find the device.

I am not familiar with the breakout cable you are using, but it looks to me that 5V and 0V (2 and 6 respecively) make sense as to the pins they are connected to on the cable. The white wire does NOT look like it is connected to pin 1 or 17 actually looks more like pin 10. SDA and SCl are on adjacent pins but your cables are connected to it looks like 1 nd 5

With power off on Pi check which pins wires are connected to on the GPIO connector using a multimeter.
I would put the 0V and 5V wires to the LCD on the Breadboard bus bars to be sure of connections.

Obviously doing some changes from rechecking has stopped the crash problem due to miswiring.

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or http://www.pcserviceselectronics.co.uk/pi/

How do you mean, how do I check the things with the multimeter? I checked the VCC, SDA and SCL against GND on the display, they all show about 4.5V, likewise on the breadboard HL-side. Breadboard LV side it's 3.3V.

chrney wrote:Hi Paul,
......
How do you mean, how do I check the things with the multimeter? I checked the VCC, SDA and SCL against GND on the display, they all show about 4.5V, likewise on the breadboard HL-side. Breadboard LV side it's 3.3V.

On resistance setting power off Pi, and check to pins on GPIO connector to your circuit to be sure you are connected correctly.

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chrney wrote:Sorry, I still don't get it - as I said, I am quite a noob here. So:

a) should I power off the Pi? That is, to pull the power cord? Not likely, but anyway, checking.
b) Where should I place the plus-"stick" of the multimeter,
c) where the minus-"stick"?

Yes pull power off Pi you cannot do resistance tests with power in a circuit.
Set meter to resistnace range 200 or 2k ohm range
Plus and minus does not matter at this point, as the meter tests the resistance between the leads

One lead on one end of a connection at the GPIO connector (preferably the back of the connector)

Other lead on the pin point of the level converter

Resistance should be less than 1 ohm for a good connection
Similarly check leads to the LCD from GPIO (5V and gnd) and leads from level shifter to LCD

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or http://www.pcserviceselectronics.co.uk/pi/